Delamination of composites modelling in Radioss

ShreyaRiadeepya
ShreyaRiadeepya Altair Community Member
in Community Q&A

For my thesis, I am modeling pin-loaded CFRPs (with thermoplastic) under a high strain rate tensile loading. For the composite, I have built it as a surface and have meshed it as 2d shell elements. With the composites browser, I have stacked the plies with the Material law 25 and property pcompp. I wish to see how the laminate fails under this loading, which also includes a possibility of delamination of plies. I'm not sure how I can do this with Radioss. I see connection materials but they require a 3d mesh, and for my specimen, the thickness is significantly lower compared to the loading direction, so 3d meshes are not required.

I am a bit confused about how I can study delamination as well with just 2d shell elements. If that isn't possible can someone tell me if there are other ways of doing this?

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Answers

  • Guilherme_Brandao
    Guilherme_Brandao
    Altair Employee

    Hi,

    There are some simplified approaches to detect delamination in 2D elements, such as the one implemented in /MAT/LAW122. Still, to accurately capture delamination one must use 3D elements (or thick shells), and consider the cohesive behavior between the different plies.

  • ShreyaRiadeepya
    ShreyaRiadeepya Altair Community Member

    I am using the Radioss 2022 version. Can I still mesh the surface geometry as a 3d element? If yes, how do I implement cohesive behavior between plies?

    Do I have to model a separate matrix layer between the plies and put them as connection materials? Apart from that, I don't see any options to model cohesive behavior. Or would you suggest something else?

  • Guilherme_Brandao
    Guilherme_Brandao
    Altair Employee

    Hello.

    If you have a surface and need to generate a 3D mesh, you must first create a 2D mesh and then perform an extrusion. You can also work with the solid geometry directly and mesh it, which would be the necessary approach for complex geometries.

    Regarding the cohesive zone definition, you will need one solid layer of cohesive elements between each ply, and these elements should have the proper cohesive property and material, such as /MAT/LAW117. All cohesive materials available are listed here: https://help.altair.com/hwsolvers/rad/topics/solvers/rad/connection_materials_starter_r.htm

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